Problem: $ { {4} \times \left[\begin{array}{rrr}{-2} & {0} & {1} \\ {-1} & {3} & {3}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{4}\times{-2} & {4}\times{0} & {4}\times{1} \\ {4}\times{-1} & {4}\times{3} & {4}\times{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-8} & {0} & {4} \\ {-4} & {12} & {12}\end{array}\right]}$